Plants have been used for medicinal application ever since man began caring for his body and health. For centuries, the world has depended on the valuable properties of plant as a source of healing. Ayurveda, Siddha, Unani and Homeopathy continue to depend predominantly on medicinal and aromatic plants as raw material for the formulation of drugs.
Medicinal Plants have attracted attention of not only professionals from various systems of Medicine, but also the scientific community belonging to different disciplines. From time immemorial, medicinal plants are known and are being used since then. Based on the considerable knowledge about these plant species from the ancient books, the modern system of medicine have enabled these plants find a place in the commercial market.
Medicinal plants are growing in importance day by day, because of the widespread interest in the adoption of multiple approaches to health care. Medicinal plants and products derived from them, have a unique place in both preventive as well as curative medicine, as these plants produce an immense and diverse array of organic compounds, called secondary metabolites. Considerable efforts are being made all over the world, to utilize more and more plant resources, as the medicine of today is found to shift from synthetic molecules to naturally synthesized molecules. Also, these naturally synthesized molecules are biologically more compatible and less toxic to human system as compared to synthetics. The majority of natural products used medicinally in plants are secondary metabolites viz., terpenoids, steroids, cardenolides, quinine lignans, flavonoids or alkaloids. Medicinal plants have gained pharmaceutical importance/therapeutic value due to its specific constituents/combination of secondary metabolites present in them. These metabolites are often differentially distributed among limited taxonomic groups within the plant kingdom and participate in interesting biological activities that can have high therapeutic value.
One such medicinal plant species that has gained pharmaceutical importance is Piper longum commonly known as long pepper. Piper longum, is a slender aromatic, perennial climber belonging to the family Piperaceae, with thin and erect branches having sessile ovate leaves. It has minute dioecious flowers on spikes (inflorescence). Fruits, which are used in medicine, are small red berries and often turns black on ripening. It grows well in tropical and subtropical climate.
The compound of medicinal interest in Piper longum is present in the female spike (inflorescence). Piper longum plant contains alkaloid piperine as one of the active ingredient. Other active ingredients present in Piper longum plant are various amides viz. futoamide (Das & Kashinatham 1998), alkamide (Das & Kashinatham 1996), a new dimmer of amide (Zang & Wang 1996), some minor amides (Kaul & Taneja 1998) and an amide alkaloid (piperlongumine).
The dry female spike of Piper longum is widely used in Ayurvedic and Unani system of medicine particularly for diseases of respiratory tract. It is a powerful stimulant of both digestive and respiratory system and has been shown to have rejuvenating effect on lungs. It is known to play an important role in aiding the thermogenic response i.e. the result of increased thyroid hormone level in the body makes Piper longum a typical Ayurvedic complementary component whose benefit is to increase the bio-availability and to enhance the uptake of the other active ingredients. It is accepted as immuno-potentiating agent (Dahanukar 1991) and has shown promises as hepato-protective medicinal plant during clinical trials (Doshi et al 1994). The root of this plant is used for stomachache and is also prescribed in palsy, gout, rheumatism and lumbago.
Cultivation of Piper longum till recently was not very common. However, with increasing market demand of Piper longum, efforts are being diverted towards systematic cultivation of Piper longum. Since Piper longum is a shade loving creeper, majority of cultivators grow them as intercrop in coffee, arecanut & coconut plantation. Laterite soil, soil rich in organic matter are suitable for cultivation of Piper longum. 
Conventionally, Piper longum is cultivated through planting matierals such as suckers, stem cuttings, seeds or rooted vine cuttings in the month between March-April and later on transplanted in June at the onset of monsoon.
The following are the drawbacks associated with conventional method of cultivation of Piper longum using seed, suckers, rooted stem cuttings respectively.
Seeds as planting material: Very rarely seeds are used as planting material, because number of viable seeds produced by one spike is very limited. Since, female spikes are the medicinal part of the plant, available seeds material for plantation is very less or limited. Moreover, Piper longum seeds are highly heterozygeous in nature hence do not ensure quality homogenous raw material production. As seeds produce heterozygous plant (offspring), hence are not a good choice material.
Suckers as planting material: Suckers are produced only from adult plants. They are produced after two years of plantation. Moreover, a plant produces very limited number of suckers, thus very small number of planting material is available. This method is commercially not very viable as, Piper longum has woody roots which develops in 2-3 years old plant. From woody roots, few suckers develop which can be used for plantation. However, this method does not provide enough planting material.
Rooted stem cuttings as planting material: The most common cultivation practice is from rooted stem cuttings. 8-10 cm long stem segments are taken from the tip of the branches & artificially rooted using rooting hormone. Only 70-80% cuttings develop rootings. These are then transplanted in monsoon to the field with as much as 95% survival. The only snag with this method is that, when from a mature plant more than 4-5 stem cuttings are taken, these plants show reduced yield and growth. It is noticed that if more than 10% plants are used from a commercial cultivation field for generating the cuttings, it severely affects the production of raw material.
The existing methods of cultivating Piper longum, is time consuming, as time is lost in preparing stem cuttings, rooted vines or suckers for plantation of Piper longum. All this reduces the plant population which plant otherwise have given female spike or roots having medicinal properties.
Contrary to this, the rate of multiplication by micropropagation is much higher and in a shorter time. Moreover, by micropropagation one can develop clones as well as somaclonal variants for selection of desired traits.
Plant regeneration by tissue culture techniques is well established. A wide variety of plant species has been successfully micropropagated in vitro via organogenesis or somatic embryogenesis. Organogenesis leads to organ formation i.e. shoot or root, which can be isolated to induce development of roots or shoots, to produce full plant. While somatic embryogenesis leads to the development of somatic embryos (embryos developed without fertilization) which have both shoot and root initials and are capable of developing into whole plant. Although the ability of individual parts of plants and cells to regenerate into complete plants called totipotency, is a well known phenomenon, each plant or plant part requires specialized studies to invent the conditions that allow such regeneration. Some of the broadly applicable factors controlling growth and differentiation of such cultures have been determined. The establishment of interactions among different groups of phytohormones and growth regulators alone or in combinations are responsible for certain interrelations existing among cells, tissues and organs. There seems to be consensus that the success in inducing differentiation depends upon the type of explant, physiological condition of the explant and physical and chemical milieu of the explant during culture. Due to this, the science of tissue culture has been directed to optimize the physiological conditions of source plant, the type of explant, the culture conditions and the phytohormones used to initiate tissue culture. This substantiates the fact that development of a new process for proliferation of plants by tissue culture is not obvious.
There is no report on micropropagation of Piper longum from lateral bud explant through direct rhizogenesis (organogenesis) followed by the plant regeneration. The scientist of the present invention have been successful in developing an efficient in vitro system of micropropagation of Piper longum from lateral bud explant through direct organogenesis.
There is an urgent need to develop a method which obviates the drawbacks of the existing protocols. Looking at above mentioned problems related to availability of planting material, it is imperative that the novel method of producing elite, homogenous planting material is developed. Keeping this in mind the present work has been undertaken. The present invention provides an efficient and cost effective method of in-vitro micropropagation of Piper longum. By this method the raw material of Piper longum produced is as high as 900 times the conventional methods, in less number of days.